JP2000243400A - Hydrogen storage alloy electrode and nickel hydrogen storage battery using it as negative electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen storage alloy electrode which can restrain voltage decrease of a nickel hydrogen storage battery at the time of high temperature storage, and the nickel hydrogen storage battery which is excellent in a high temperature storage characteristic by the use of the hydrogen storage alloy electrode. SOLUTION: A nickel hydrogen storage battery is constructed such that at least one kind of compound which is selected from a group of an oxidation Co compound and a Cu compound, and at least one kind of compound which is selected from a group of a Mo compound, a W compound, a Zn compound, an Nb compound, a Y compound, a Yb compound and an Er compound are contained in a hydrogen storage alloy electrode of which a main active material is a hydrogen storage alloy, and the hydrogen storage alloy electrode is used as a negative electrode 2 of the nickel hydrogen storage battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hydrogen storage alloy electrode and a nickel-metal hydride storage battery using the same as a negative electrode.

[0002]

2. Description of the Related Art A nickel-metal hydride storage battery is a storage battery using a hydrogen storage alloy electrode as a negative electrode. In recent years, with the miniaturization of portable electronic devices that use a storage battery as a main power source, the number of opportunities for portable use has increased. It is becoming more widely used. Therefore, storage batteries are required to exhibit stable performance without being affected by environmental changes (particularly temperature changes). For example, when used for laptop computers and mobile phones,
Even at high and low temperatures, characteristics equivalent to those at normal temperature are required, and the demand for batteries is increasing. Therefore, studies have been continued on further improving the temperature characteristics of the storage batteries used in such electronic devices.

[0003]

As the positive electrode of the nickel-metal hydride storage battery, there are a sintered positive electrode and a non-sintered positive electrode, both of which use nickel hydroxide as a main active material. In a non-sintered positive electrode, nickel hydroxide, which is the main active material, is dispersed in water or a solvent together with a binder, a thickener, etc. to form a paste, which is then applied to a conductive porous substrate serving as a current collector. Since it is manufactured by filling, there is a problem that the distance between the active material and the base material is increased, and the utilization rate of the active material is reduced. Therefore, in the non-sintered type positive electrode, metallic cobalt or a cobalt compound such as cobalt monoxide or cobalt hydroxide is added to the positive electrode in order to increase the utilization rate and achieve a high capacity. These cobalt additives provide Co, CoO, Co
It is known that a change of (OH) ₂ → CoOOH occurs to form a cobalt network for electrically connecting nickel hydroxide particles.

In a nickel-metal hydride storage battery, the negative electrode has a capacity larger than that of the positive electrode, thereby suppressing gas generation from the negative electrode at the end of charging and at the end of discharging, and absorbing oxygen gas generated from the positive electrode at the negative electrode. Sealing is realized. In other words, even after the positive electrode has been fully charged or completely discharged during charging, the negative electrode has an uncharged portion or an undischarged portion, whereby oxygen gas can be preferentially generated from the positive electrode. It is necessary to adopt a configuration that can prevent generation of gas. The excess capacity of the negative electrode during this discharge (discharge reserve) is not directly involved in the charge / discharge reaction, but is necessary to discharge the positive electrode capacity until the end of discharge, and mainly forms the cobalt network in the positive electrode described above. It is formed on the negative electrode as a counter reaction to the reaction and other side reactions (such as alloy corrosion).

However, according to the study of the present inventors, a nickel-metal hydride storage battery using the above-mentioned non-sintered positive electrode is:
It was found that when left in a high temperature environment, the battery voltage was significantly reduced. Since the voltage drop during storage greatly affects the subsequent battery capacity, it is extremely important for the nickel-metal hydride storage battery to improve the high-temperature storage characteristics as described above.

The present invention solves the above-mentioned problems in the prior art, and a hydrogen storage alloy electrode capable of suppressing a voltage drop of a nickel-metal hydride storage battery during high-temperature storage, and a nickel having excellent high-temperature storage characteristics using the same. It is intended to provide a hydrogen storage battery.

[0007]

Means for Solving the Problems The present inventors have prepared a hydrogen storage alloy electrode containing a hydrogen storage alloy as a main active material together with at least one compound selected from the group consisting of an oxidized Co compound and a Cu compound. , A Mo compound, a W compound, a Zn compound, a Nb compound, a Y compound, a Yb compound, and an Er compound to contain at least one compound selected from the group consisting of: Further, by using the above-mentioned hydrogen storage alloy electrode as a negative electrode, a nickel-metal hydride storage battery having excellent high-temperature storage characteristics is provided, and the above-mentioned problem has been solved.

The following is a description of the progress of the present inventors in completing the present invention as follows.

First, the present inventors analyzed the cause of the voltage drop during high-temperature storage, and found that a discharge reserve was applied to the negative electrode due to an increase in the equilibrium dissociation pressure of the hydrogen storage alloy accompanying an increase in the ambient temperature during storage. It has been found that hydrogen that should not be released originally was released as hydrogen gas into the battery, and this is caused by reducing the positive electrode.

Based on the above findings, the present inventors consider that it is effective to reduce the amount of hydrogen in the discharge reserve in order to suppress the voltage drop during storage. An attempt was made to add various metal compounds to the negative electrode. That is, by including the metal compound in the negative electrode, a part of the hydrogen in the discharge reserve is used for reduction from the metal compound to the metal, thereby reducing the reduction at the positive electrode and suppressing the voltage drop. Expected. In addition, the metal compound added for this purpose needs to have a guaranteed metal state within the working potential range of a normal hydrogen storage alloy electrode. Therefore, the present inventors have found that among various metal compounds, an oxidized Co (cobalt compound) or Cu (copper) compound is effective, and in particular, an oxidized Co compound or Cu compound added to a negative electrode is hydrogen-absorbing. This was considered to be preferable from the viewpoint of having a catalytic action to enhance the reactivity of the alloy, and this was examined.

First, the present inventors have proposed that the above-mentioned oxidized Co
A study was made on the negative electrode in which the addition method, type, and addition amount of the compound or Cu compound were variously changed. The method of dissolving these ions in the electrolytic solution was insufficient for reducing hydrogen in the discharge reserve due to the low solubility. It was found that a large amount could not be contained in the negative electrode. It was also found that when these compounds were added directly to the negative electrode, long-term storage characteristics could be improved, but at the beginning of storage, on the contrary, voltage drop was promoted.

[0012] Therefore, the present inventors have further conducted the above study, and as a result, together with at least one compound selected from the group consisting of an oxidized Co compound or a Cu compound, a Mo compound, a W compound, and the like. It has been found that by containing at least one compound selected from the group consisting of Zn compounds, Nb compounds, Y compounds, Yb compounds and Er compounds, a remarkable voltage drop at the beginning of high-temperature storage can be suppressed.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a Co compound in an oxidized state to be contained in a hydrogen storage alloy may be in the form of an oxide, hydroxide or complex of Co.
Among them, CoO, α-Co (OH) ₂ , β-Co
(OH) _{2 and the} like are preferable. As the Cu compound in the oxidized state, Cu oxides, hydroxides and complexes can be used. Among them, CuO, Cu (O
H) _{2 and the} like are preferred. In the present invention, these Co compounds and Cu compounds can be used alone or in combination of two or more.

By containing these oxidized Co compounds and Cu compounds in the hydrogen storage alloy electrode, they are reduced to a metal at a noble potential by the charge and discharge reaction of the hydrogen storage alloy electrode. By replacing some of the hydrogen in the discharge reserve with hydrogen that reduces this metal,
The amount of hydrogen in the discharge reserve is reduced, the reduction of the conductive network of cobalt formed in the positive electrode is suppressed, and the voltage drop is suppressed.

That is, as described above, when a non-sintered electrode is used for the positive electrode of a nickel-metal hydride storage battery, a cobalt compound such as metal cobalt or cobalt monoxide is added. Dissolved as divalent cobalt ions during the standing period or the first charge after the injection of the electrolytic solution, and precipitated as cobalt hydroxide between the nickel hydroxide particles and on the conductive porous base material serving as the current collector. As the charging proceeds, it is oxidized to cobalt oxyhydroxide having excellent conductivity.

On the other hand, hydrogen corresponding to the oxidation reaction of cobalt and the counter reaction such as alloy corrosion is occluded in the negative electrode as a discharge reserve. The hydrogen stored as this discharge reserve is not released by the normal charge / discharge reaction, but when the battery is stored in a high-temperature atmosphere, the hydrogen storage alloy becomes hydrogen gas as the equilibrium pressure of the hydrogen storage alloy increases. , Which reduces the conductive network of cobalt formed on the positive electrode, causing a voltage drop.

The discharge reserve formed on the negative electrode is formed by adding not only the reaction of the formation reaction of the conductive network but also the hydrogen by the reaction of the side reaction (such as alloy corrosion). It has more hydrogen than it can reduce the network. Therefore, it is conceivable to reduce only the amount of hydrogen originally stored as a discharge reserve in the negative electrode. However, since this discharge reserve is formed in conjunction with a conductive network of cobalt of the positive electrode, the discharge reserve of the negative electrode is reduced. This means that the reserve alone cannot be reduced. Therefore, in the present invention, as described above,
At least one compound selected from the group consisting of a Co compound and a Cu compound in an oxidized state is contained, whereby a part of the hydrogen in the discharge reserve is consumed and the amount of hydrogen in the discharge reserve is reduced. .

In the present invention, the content of at least one compound selected from the group consisting of the Co compound and the Cu compound in the oxidized state depends on the amount of discharge reserve, but is usually 100 parts by weight of the hydrogen storage alloy. On the other hand, 0.
It is preferably 5 parts by weight or more and 5 parts by weight or less, more preferably 1 part by weight or more and 3 parts by weight or less.

By including at least one compound selected from the group consisting of the Co compound and the Cu compound in the above-described oxidation state in the hydrogen storage alloy, the amount of hydrogen in the discharge reserve is reduced, and the conductivity of the positive electrode is reduced. Can reduce the voltage drop during high-temperature storage by reducing the reduction of the conductive network.However, the hydrogen storage alloy electrode to which these compounds are added is effective for long-term storage, but significantly increases the voltage in the initial stage of storage. descend.

The present inventors have conducted various studies to solve the above-mentioned problems. As a result, the Co compound and Cu
At least one compound selected from the group consisting of Mo compounds, W compounds, Zn compounds, Nb compounds, Y compounds, Yb compounds, and Er compounds is used together with at least one compound selected from the group consisting of compounds. It has been found that, by containing it in the above, a remarkable voltage drop at the initial stage of storage as described above can be suppressed.

In the present invention, at least one compound selected from the group consisting of the above-mentioned Mo compound, W compound, Zn compound, Nb compound, Y compound, Yb compound and Er compound is contained in the hydrogen-absorbing alloy so that it can be stored early. The reason why the voltage drop can be suppressed at this time is not necessarily clear at present, but it is considered to be probably because the above compound can suppress the alloy corrosion reaction that forms a part of the discharge reserve. Therefore, discharge is caused by a decrease in the amount of hydrogen by at least one compound selected from the Mo compound and the like and a decrease in the amount of hydrogen by at least one compound selected from the group consisting of the Co compound and the Cu compound in the oxidation state. By reducing the amount of hydrogen in the reserve, even during high-temperature storage, the generation of hydrogen gas from the negative electrode is suppressed, and the reduction of the conductive network in the positive electrode is reduced. It is thought that the high temperature storage characteristics could be improved also in the above. Further, the above Mo compound, W compound, Zn compound, Nb compound, Y
By using at least one compound selected from the group consisting of compounds, Yb compounds and Er compounds,
As compared with the case where only the Co compound or the Cu compound in the oxidized state is contained, the voltage drop at the initial stage of storage is suppressed, so that the overall effect is raised, and the voltage drop can be further suppressed even during the long storage period. Become like

In the present invention, at least one compound selected from the group consisting of Mo compounds, W compounds, Zn compounds, Nb compounds, Y compounds, Yb compounds and Er compounds is an oxide, a hydroxide, And the like, and among them, it is preferable to use an oxide which is easy to handle.

As specific examples of the above compounds, Mo compounds include, for example, K ₂ MoO ₄ , Li ₂ MoO ₄ ,
Na ₂ MoO ₄ , MoO ₃ , CoMoO _4, etc.
Examples of the W compound include K ₂ WO ₄ and Li ₂ W
There are O ₄ , Na ₂ WO ₄ , WO _3, etc., as the Zn compound, for example, ZnO, and as the Nb compound,
For example, there are NbO, NbO ₂ , Nb ₂ O _5, etc.
Examples of the compound include Y ₂ O ₃ and Y (OH) _3, and examples of the Er compound include Er ₂ O ₃ and E
r (OH) ₃ and the like.

In the present invention, the content of at least one compound selected from the group consisting of the Mo compound, W compound, Zn compound, Nb compound, Y compound, Yb compound and Er compound in the hydrogen storage alloy electrode is as follows. , 0.2 parts by weight or more based on 100 parts by weight of the hydrogen storage alloy,
It is preferably at most 0.5 part by weight, more preferably at least 0.5 part by weight and up to 2 parts by weight.

The hydrogen storage alloy electrode of the present invention is usually produced by dispersing the hydrogen storage alloy and the above compound together with a binder or the like in water or a solvent and filling the same with a base material. However, the manufacturing method of the hydrogen storage alloy electrode is not limited to the above method as long as it is a non-sintering type, and another method may be used. As the hydrogen storage alloy, AB mainly composed of Zr, Ni, Mn, etc.
There are AB type ₅ alloys such as type ₂ alloys and Mm (La, Ce, Nd, Pr) -Ni type. Among them, Mm-Ni
Part of Ni is Mn, Co, Al, Mg, C
Alloys substituted with at least one element selected from the group consisting of u and Cr are preferable. These alloys can be expected to have a high capacity at a low hydrogen equilibrium pressure, but have a large amount of hydrogen gas generated from the negative electrode because they contain a large amount of transition metals. For this reason, conventionally, there was a risk that the high-temperature storage characteristics could be reduced. However, in the present invention, there is no such a possibility, and the characteristics can be effectively exhibited, so that it is particularly useful. In addition, among hydrogen storage alloys substituted with a plurality of transition metals, a high-capacity non-stoichiometric hydrogen storage alloy having a large content of rare earth element La or the like in Mm (for example, another hydrogen storage alloy with respect to Mm1) Ni,
A hydrogen storage alloy having a total amount of Co, Mn, Al, and the like of 5.02 to 5.45) has a large amount of transition metal present on the alloy surface and a large amount of hydrogen gas, and for the same reason as described above, In the present invention, the characteristics can be effectively exhibited, and it is particularly useful.

In the nickel-metal hydride storage battery of the present invention, the above-mentioned hydrogen storage alloy electrode is used as a negative electrode, and a non-sintered nickel electrode is used as a positive electrode. For example, they are spirally wound with a separator interposed therebetween. It is manufactured through a process of inserting into a battery can, injecting an electrolytic solution, and sealing.

For the positive electrode, a paste is prepared by mixing nickel hydroxide powder and a cobalt compound such as cobalt metal or cobalt monoxide as a conductive aid with a binder such as carboxymethylcellulose or polytetrafluoroethylene. It is produced by being supported on a conductive porous substrate made of a foam or the like and dried. At that time, the paste may contain a nickel powder having an average particle diameter of 3 μm or less as another conductive aid. As the addition amount of the cobalt metal or the cobalt compound,
Nickel hydroxide 10
It is preferably 0.5 to 10 parts by weight, more preferably 1 to 5 parts by weight, based on 0 part by weight in terms of cobalt.

As the nickel hydroxide used in the present invention, conventionally known nickel hydroxide can be used, and among them, a surface on which a conductive network can be formed by a small amount of a cobalt compound is cobalt hydroxide. (1 to 8% by weight based on the nickel hydroxide) is preferably used.

The nickel-metal hydride storage battery of the present invention
The positive electrode and the negative electrode as described above are wound through a separator, inserted into a battery can, and then manufactured through a process of injecting an alkaline electrolyte. In order to form a conductive network, both the positive electrode and the negative electrode are assembled in a non-chemical state in which neither charging nor discharging is performed electrochemically. That is, by combining electrodes that have not undergone either charging or discharging, the metal cobalt or cobalt compound added to the positive electrode is oxidized by aging or initial charging after battery assembly, and the discharge reserve described above is accompanied by the reaction. Is formed on the negative electrode, and a positive electrode regulated battery can be obtained.

[0030]

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the following, “parts” means “parts by weight”.

Example 1 2.9 parts of cobalt monoxide powder was added to 100 parts of nickel hydroxide powder coated with 4.7% by weight of cobalt hydroxide,
5 parts by weight of an aqueous carboxymethylcellulose solution and 5 parts of a 60% by weight polytetrafluoroethylene dispersion were added and mixed to form a paste. This paste was filled and supported on a substrate made of a nickel foam, and after drying and pressure regulation, it was cut into a predetermined size to produce a sheet-shaped non-sintered nickel electrode.

Apart from the above, the composition is MmNi _4.05 Co
_0.45 Mn _0.5 Al _0.35 (The composition of Mm is La: 0.32 at%, Ce: 0.48 at%, Nd: 0.15 at%,
Pr: 0.04 atomic%, Ni, CO, Mm1
2.5 parts of CoO, 1 part of Y ₂ O _3, and 2 parts of nickel powder were added to 100 parts of a hydrogen storage alloy having a total of 5.35) of Mn and Al, and a carboxymethyl cellulose aqueous solution and polytetrafluoroethylene were further added. The dispersion was added to form a paste. A predetermined amount of this paste was applied to both surfaces of a perforated iron-nickel-plated steel sheet, and after drying and pressure regulation, it was cut into a predetermined size to produce a sheet-shaped non-sintered hydrogen storage alloy electrode.

The hydrogen-absorbing alloy electrode prepared as described above is used as a negative electrode, the above-mentioned non-sintered nickel electrode is used as a positive electrode, and these are opposed to each other via a sulfonated polypropylene separator. The wound electrode assembly was inserted into a battery can, a predetermined amount of a 30% by weight aqueous solution of potassium hydroxide was injected as an electrolytic solution, and the battery was sealed to produce a nickel-metal hydride storage battery having the structure shown in FIG.

Now, the nickel-metal hydride storage battery shown in FIG. 1 will be described. The positive electrode 1 is made of a non-sintered nickel electrode using the above-mentioned nickel hydroxide as an active material, and the negative electrode 2 is made of the above-mentioned hydrogen storage alloy as an active material. , A non-sintered hydrogen storage alloy electrode containing CoO and Y ₂ O ₂ .
Does not show details of the positive electrode 1 and the negative electrode 2,
The base material and the like are omitted to show a single configuration.
Then, the positive electrode 1 and the negative electrode 2 are overlapped with a separator 3 interposed therebetween, spirally wound and inserted into the battery can 5 as an electrode body 4 having a wound structure, and an insulator 14 is disposed on the upper part thereof. ing. An insulator 13 is provided on the bottom of the battery can 5 before the electrode body 4 is inserted.

The annular gasket 6 is made of nylon 66, and the battery lid 7 is composed of a terminal plate 8, a sealing plate 9, a metal spring 10 and a valve body 11 disposed in an internal space formed by the terminal plate 8, a sealing plate 9, and a battery can. The opening 5 is sealed with the battery cover 7 or the like. That is, after inserting the wound electrode body 4 and the insulators 13 and 14 into the battery can 5, an annular groove 5 a having a bottom protruding inward is formed in the vicinity of the open end of the battery can 5. The annular gasket 6 and the battery lid 7 are arranged in the opening of the battery can 5 by supporting the lower portion of the annular gasket 6 by the inner peripheral side protruding portion of the groove 5a. The opening of the battery can 5 is sealed by being tightened inward. The terminal plate 8 is provided with a gas discharge hole 8a, the sealing plate 9 is provided with a gas detection hole 9a, and a metal spring 10 and a valve body 11 are arranged between the terminal plate 8 and the sealing plate 9. ing. Then, the outer peripheral portion of the sealing plate 9 is bent to sandwich the outer peripheral portion of the terminal plate 8, thereby fixing the terminal plate 8 and the sealing plate 9.

Under normal circumstances, this battery is a metal spring 1
Since the valve body 11 closes the gas detection hole 9a by the pressing force of 0, the inside of the battery is kept in a sealed state, but gas is generated inside the battery and the pressure inside the battery rises abnormally. , The metal spring 10 contracts to form a gap between the valve body 11 and the gas detection hole 9a, and gas inside the battery passes through the gas detection hole 9a and the gas discharge hole 8a and is discharged to the outside of the battery. As a result, when the battery internal pressure decreases and the battery internal pressure returns to normal, the metal spring 10 is restored to the original state,
The pressing force causes the valve body 11 to close the gas detection hole 9a again to keep the inside of the battery in a sealed structure.

The positive electrode lead body 12 is made of a nickel ribbon, one end of which is spot-welded to the exposed portion of the base material at the outermost periphery of the positive electrode 2, and the other end is spot-welded to the lower end of the sealing plate 9. And the terminal plate 8 is connected to the sealing plate 9.
And can function as a positive electrode terminal. As described above, the base material is exposed on the outer surface of the outermost peripheral portion of the negative electrode 2, and the base material contacts the inner wall of the battery can 5, whereby the battery can 5 functions as a negative electrode terminal. .

Comparative Example 1 A nickel-metal hydride battery was produced in the same manner as in Example 1, except that the hydrogen-absorbing alloy electrode used as the negative electrode did not contain CoO and Y ₂ O _3. did.

Comparative Example 2 A nickel-metal hydride storage battery was prepared in the same manner as in Example 1, except that the hydrogen-absorbing alloy electrode used as the negative electrode did not contain CoO.

Comparative Example 3 A nickel-metal hydride storage battery was prepared in the same manner as in Example 1, except that the hydrogen-absorbing alloy electrode used as the negative electrode did not contain Y ₂ O ₃ .

The nickel-metal hydride storage batteries of Example 1 and Comparative Examples 1 to 3 manufactured as described above were held at 60 ° C. for 17 hours, charged at 25 ° C. and 0.2 CA for 7 hours, and charged at 0.2 C.
After repeating discharge A (final voltage 1.0 V) for 5 cycles, the high-temperature storage characteristics were examined.

The high-temperature storage characteristics were measured by measuring the voltage change when the battery in the discharge completed state was kept at 80 ° C. for 14 days. The result is shown in FIG.

As shown in FIG. 2, the battery of Example 1 exhibited a smaller voltage drop with an increase in the number of storage days and was excellent in high-temperature storage characteristics as compared with the batteries of Comparative Examples 1 to 3.

The battery after the high-temperature storage test was kept at 25 ° C.
The battery was charged at 0.2 CA for 7 hours and discharged at 0.2 CA (final voltage: 1.0 V), and the ratio to the discharge capacity before storage was determined by the following formula, and evaluated as a recovery rate. Table 1 shows the results.

Recovery rate (%) = (discharge capacity before storage / discharge capacity after storage) × 100

[0046]

[Table 1]

As shown in Table 1, the battery of Example 1 has a higher recovery rate after high-temperature storage than the batteries of Comparative Examples 1 to 3, and also has excellent high-temperature storage characteristics. It was clear.

In the above embodiment, CoO and Y ₂ O ₃
Is used in combination with the hydrogen storage alloy electrode, but α-Co (OH) ₂ and β-Co are used instead of CoO.
Similar effects were confirmed when (OH) ₂ was used.
In addition, when the hydrogen storage alloy electrode contains a Cu compound in an oxidized state and at least one compound selected from the group consisting of Mo compounds, W compounds, Zn compounds, Nb compounds, Yb compounds, and Er compounds. Similarly, it was confirmed that the voltage drop during high-temperature storage can be suppressed.

[0049]

As described above, according to the present invention,
A hydrogen storage alloy electrode capable of suppressing a voltage drop of a nickel-metal hydride storage battery during high-temperature storage and a nickel-metal hydride storage battery having excellent high-temperature storage characteristics using the same as a negative electrode were provided.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing an example of a nickel-metal hydride storage battery according to the present invention.

FIG. 2 is a diagram showing the high-temperature storage characteristics of the battery of Example 1 of the present invention and the batteries of Comparative Examples 1 to 3.

[Explanation of symbols]

 1 positive electrode 2 negative electrode 3 separator

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masato Isogai 1-1-88 Ushitora, Ibaraki City, Osaka Prefecture Inside Hitachi Maxell Co., Ltd. (72) Inventor Ryu Nagai 1-188 Ushitora, Ibaraki City, Osaka Prefecture Hitachi Maxell F term (reference) 5H003 AA03 BB02 BB04 BD03 5H016 AA02 EE01 EE04 EE05 HH01 5H028 AA02 EE01 EE04 FF03 FF05 HH01

Claims (4)

[Claims] 1. A hydrogen storage alloy electrode containing a hydrogen storage alloy as a main active material, wherein said hydrogen storage alloy electrode contains at least one compound selected from the group consisting of a oxidized Co compound and a Cu compound. And a Mo compound,
A hydrogen storage alloy electrode comprising at least one compound selected from the group consisting of a W compound, a Zn compound, a Nb compound, a Y compound, a Yb compound and an Er compound. 2. The Co compound in an oxidized state is CoO, α-
The hydrogen storage alloy electrode according to claim 1, wherein the electrode is at least one selected from the group consisting of Co (OH) ₂ and β-Co (OH) ₂ . 3. The hydrogen storage alloy electrode according to claim 1, wherein the oxidized Cu compound is at least one selected from the group consisting of CuO and Cu (OH) ₂ . 4. A nickel-metal hydride storage battery using the hydrogen storage alloy electrode according to claim 1 as a negative electrode.